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Biomedical subjects

J Foucher

Publications and source records attributed to J Foucher.

At least 19 recordsLinked to original sources
PubMed2006

Diagnosis of liver fibrosis by transient elastography (FibroScan) and non-invasive methods in Crohn's disease patients treated with methotrexate.

BACKGROUND: Methotrexate is an effective treatment in Crohn's disease, which may induce liver fibrosis with high cumulative doses. Transient elastography (FibroScan, Echosens, Paris, France) is a new non-invasive rapid, allowing assessment of liver fibrosis by measurement of liver stiffness. AIM: A prospective study to evaluate liver fibrosis with FibroScan and non-invasive biochemical methods in Crohn's disease patients treated with methotrexate. METHODS: Consecutive Crohn's disease patients had evaluation of liver fibrosis with non-invasive methods. Two subgroups of patients were compared: cumulative dose of methotrexate of more than 1500 mg (group 1) and naive for methotrexate (group 2). Liver biopsy was performed in patients with persistent liver enzyme abnormalities or FibroScan value >8.7 kPa. RESULTS: Fifty-four consecutive Crohn's disease patients were fully investigated (45 females, mean age 41 +/- 14 years). Median FibroScan values were similar in group 1 (n = 21) and in group 2 (n = 33), 5.5 and 4.5 kPa, respectively. FibroScan values were not correlated with the cumulative dose of methotrexate. CONCLUSION: In Crohn's disease patients treated with a high dose of methotrexate, significant liver fibrosis is rare and not accurately detected with liver enzymes abnormalities. FibroScan could be recommended and liver biopsy could be performed only with patients with high values and/or with chronic liver enzymes abnormalities.

Adult↗
PubMed2005

Diagnosis of cirrhosis by transient elastography (FibroScan): a prospective study.

BACKGROUND: Transient elastography (FibroScan) is a new, non-invasive, rapid, and reproducible method allowing evaluation of liver fibrosis by measurement of liver stiffness. In cirrhotic patients, liver stiffness measurements range from 12.5 to 75.5 kPa. However, the clinical relevance of these values is unknown. The aim of this prospective study was to evaluate the accuracy of liver stiffness measurement for the detection of cirrhosis in patients with chronic liver disease. METHODS: A total of 711 patients with chronic liver disease were studied. Aetiologies of chronic liver diseases were hepatitis C virus or hepatitis B virus infection, alcohol, non-alcoholic steatohepatitis, other, or a combination of the above aetiologies. Liver fibrosis was evaluated according to the METAVIR score. RESULTS: Stiffness was significantly correlated with fibrosis stage (r=0.73, p<0.0001). Areas under the receiver operating characteristic curve (95% confidence interval) were 0.80 (0.75-0.84) for patients with significant fibrosis (F>2), 0.90 (0.86-0.93) for patients with severe fibrosis (F3), and 0.96 (0.94-0.98) for patients with cirrhosis. Using a cut off value of 17.6 kPa, patients with cirrhosis were detected with a positive predictive value and a negative predictive value (NPV) of 90%. Liver stiffness was significantly correlated with clinical, biological, and morphological parameters of liver disease. With an NPV>90%, the cut off values for the presence of oesophageal varices stage 2/3, cirrhosis Child-Pugh B or C, past history of ascites, hepatocellular carcinoma, and oesophageal bleeding were 27.5, 37.5, 49.1, 53.7, and 62.7 kPa, respectively. CONCLUSION: Transient elastography is a promising non-invasive method for detection of cirrhosis in patients with chronic liver disease. Its use for the follow up and management of these patients could be of great interest and should be evaluated further.

Adult↗
PubMed2004

Neural correlates of implicit object identification.

The present study sought to assess neural correlates of implicit identification of objects by means of fMRI, using tasks that require matching of the physical properties of objects. Behavioural data suggests that there is automatic access to object identity when observers attend to a physical property of the form of an object (e.g. the object's orientation) and no evidence for semantic processing when subjects attend to colour. We evaluated whether, in addition to neural areas associated with decisions to specific perceptual properties, areas associated with access to semantic information were activated when tasks demanded processing of the global configuration of pictures. We used two perceptual matching tasks based on the global orientation or on the colour of line drawings. Our results confirmed behavioural data. Activations in the inferior occipital cortex, fusiform and inferior temporal gyri in both tasks (orientation and colour) account for perceptual and structural processing involved in each task. In contrast, activations in the posterior and medial parts of the fusiform gyrus, shown to be involved in explicit semantic judgements, were more pronounced in the orientation-matching task, suggesting that semantic information from the pictures is processed in an implicit way even when not required by the task. Thus, this study suggests that cortical regions usually involved in explicit semantic processing are also activated when implicit processing of objects occurs.

Adult↗
PubMed2001

Comparison of Hilbert transform and wavelet methods for the analysis of neuronal synchrony.

The quantification of phase synchrony between neuronal signals is of crucial importance for the study of large-scale interactions in the brain. Two methods have been used to date in neuroscience, based on two distinct approaches which permit a direct estimation of the instantaneous phase of a signal [Phys. Rev. Lett. 81 (1998) 3291; Human Brain Mapping 8 (1999) 194]. The phase is either estimated by using the analytic concept of Hilbert transform or, alternatively, by convolution with a complex wavelet. In both methods the stability of the instantaneous phase over a window of time requires quantification by means of various statistical dependence parameters (standard deviation, Shannon entropy or mutual information). The purpose of this paper is to conduct a direct comparison between these two methods on three signal sets: (1) neural models; (2) intracranial signals from epileptic patients; and (3) scalp EEG recordings. Levels of synchrony that can be considered as reliable are estimated by using the technique of surrogate data. Our results demonstrate that the differences between the methods are minor, and we conclude that they are fundamentally equivalent for the study of neuroelectrical signals. This offers a common language and framework that can be used for future research in the area of synchronization.

Brain↗
PubMed2000

Automatic object identification: an fMRI study.

Boucart and Humphreys reported an automatic access to object identity when observers attend to a physical property of the form of an object (e.g. the orientation) but not to its colour. We sought evidence for automatic identification in a brain imaging study using fMRI. In an orientation decision task participants decided whether a picture was vertical or horizontal. In the colour decision task participants decided if a picture was blue or green. Activation of areas 18-19 was found for both color and orientation. Activation of the temporal area 37 occurred more frequently in the orientation than in the colour decision task. This result suggests that automatic identification activates the same brain area as overt processing of semantic information.

Adult↗
PubMed1996

Non-steroidal anti-inflammatory drugs and variceal bleeding: a case-control study.

BACKGROUND/AIM: The aim of this case-control study was to assess the risk of bleeding from esophageal varices associated with aspirin and non-steroidal anti-inflammatory drug consumption. METHODS: Between January 1992 and May 1994, patients admitted for bleeding from esophageal or gastric lesions related to portal hypertension were matched with a control patient of the same age and sex, who was free of gastrointestinal bleeding. A structured interview was conducted with the cases and controls to determine drug consumption during the 2 weeks preceding admission. Fifty-nine cases and 59 controls were recruited. RESULTS/CONCLUSIONS: Use of aspirin was more prevalent among the cases than the controls (odds ratio 3.81; 95% confidence interval 1.36-11.64; p = 0.004). This difference remained significant in the subgroups of patients with a first episode of variceal bleeding (odds ratio 3.9; 95% confidence interval 1.2-13.9, p = 0.01), but was not significant in the subgroups of patients with a recurrent episode of variceal bleeding. The use of aspirin was associated with a high risk of a first episode of variceal bleeding, suggesting that patients with portal hypertension should avoid taking these drugs.

Adult↗